Mt. Battle, the 100 Man Melee of sorts. This walkthrough deals with it in Scenario Mode. This is a great way to train your Pokémon and earn Pokécoupons

Notes:
Your team will be completely healed after each battle. After every 10 fights, you can go back to the base of the mountain and if you've defeated the area leader, you can skip ahead to the next area so you do not have to fight the previous trainers all over again.